The release of the audio comes just two days after White House counterterrorism adviser John Brennan visited the Yemeni capital of Sanaa to meet with its new president, Abed Rabbo Mansour Hadi, to discuss ramping up the battle against al-Qaida affiliated militants who now control large swaths of the country's southern region.

While there is still no public translation of the new Zawahiri audio message, a U.S. government official familiar with the contents tells NBC News it was clearly recorded before the news broke last week about a foiled plot to blow up a U.S. airliner with more-sophisticated underwear bomb.

The message discusses the transition from exiled former Yemeni president Ali Abdullah Saleh to Hadi, said the official, speaking on condition of anonymity.

NBC News terror analyst Evan Kohlmann notes that there is typically a two- to three-week lapse between the events described in Zawahiri’s messages and their public release. (Kohlmann's Flashpoint Intel service is working to translate the message, but he gives the title as, "Yemen: Between a Fugitive Puppet and a Collaborating Stooge," apparent references to Saleh and Hadi.)